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From: Nick Piggin <piggin@cyberone.com.au>
To: "Martin J. Bligh" <mbligh@aracnet.com>
Cc: Con Kolivas <kernel@kolivas.org>,
	Davide Libenzi <davidel@xmailserver.org>,
	Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] Fix find busiest queue 2.6.0-test9
Date: Mon, 10 Nov 2003 11:59:12 +1100	[thread overview]
Message-ID: <3FAEE2E0.2040306@cyberone.com.au> (raw)
In-Reply-To: <125870000.1068397851@[10.10.2.4]>



Martin J. Bligh wrote:

>On the same vein ... this looks odd:
>
>         * We fend off statistical fluctuations in runqueue lengths by
>         * saving the runqueue length during the previous load-balancing
>         * operation and using the smaller one the current and saved lengths.
>         * If a runqueue is long enough for a longer amount of time then
>         * we recognize it and pull tasks from it.
>...
>        if (idle || (this_rq->nr_running > this_rq->prev_cpu_load[this_cpu]))
>                nr_running = this_rq->nr_running;
>        else
>                nr_running = this_rq->prev_cpu_load[this_cpu];
>
>It says we uses the smaller of the two in the comment, but then it seems to
>use the > of the two in the code? Unless I'm losing it, which is likely ;-)
>

You want the larger of the two values to be taken for the destination
queue, and the smaller to be taken for the source queue. This way you
get a minimal imbalance.



  reply	other threads:[~2003-11-10  1:10 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-08 16:49 Con Kolivas
2003-11-08 22:41 ` Nick Piggin
2003-11-08 22:58 ` Andrew Morton
2003-11-08 23:42   ` Nick Piggin
2003-11-09  0:44     ` Davide Libenzi
2003-11-09 15:34       ` Martin J. Bligh
2003-11-09 15:53         ` Davide Libenzi
2003-11-09 15:58           ` Martin J. Bligh
2003-11-09 16:05             ` Davide Libenzi
2003-11-09 16:07               ` Con Kolivas
2003-11-09 17:10                 ` Martin J. Bligh
2003-11-10  0:59                   ` Nick Piggin [this message]
2003-11-10  7:46               ` Ingo Molnar
2003-11-09 15:59           ` Con Kolivas
2003-11-09 16:48             ` Martin J. Bligh
2003-11-09 17:27               ` Davide Libenzi
2003-11-09 20:39                 ` Martin J. Bligh

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